add emscripten

Dockerfile

@@ -19,7 +19,7 @@ RUN wget -O - https://github.com/libevent/libevent/releases/download/release-2.0
 FROM git-registry.moenext.com/mycard/docker-runner-base:latest
 
 RUN apt update && \
-    apt -y install git build-essential libgl1-mesa-dev libglu-dev libxxf86vm-dev && \
+    apt -y install git build-essential libgl1-mesa-dev libglu-dev libxxf86vm-dev emscripten && \
     rm -rf /var/lib/apt/lists/* /var/cache/* /tmp/* /var/tmp/* /var/log/*
 
 COPY --from=premake-builder /usr/src/premake/bin/release/premake5 /usr/bin/premake5